After the ASHRAE meetings, and during the AHR conference, several of us are getting together to discuss building system metadata. The goal is to define interfaces to support quick fast integrations of building systems into the wider world. This is the first of several posts describing this interface. Drop me a line or watch for announcements from LONmark if you want to join us for discussion.
In my smart grid work, I began describing each end node as a microgrid. A microgrid is a self-contained entity responsible for managing its own energy use, generation, storage, conversion, and as a last resort, market operations. This model eliminates direct grid control of buildings. Maximum grid incentives, all delivered to a single energy services interface (ESI), the locus of market bidding for the building.
The ESI is the external face of the participants in smart energy. The ESI facilitates the communications among the entities that produce and distribute electricity and the entities that manage the consumption of electricity. An ESI may be in front of one system or several, one building or several, or even in front of a microgrid. In keeping with service integration principles, there is no direct interaction across the ESI.
Today, an ESI is most often on the outside of a building system. The leaders in commercial energy management, companies like Target, put the business between the ESI and the building systems. Target evaluates energy use, and changes in energy use as normal business decisions, and building systems respond to business operations. Target though, is unusually aware of its decision processes, has many nearly identical buildings, and has strict commissioning standards. For the rest of us to be like Target, we need a Building Systems Interface (BSI).
The BSI must expose several services. New systems will certainly incorporate the market-oriented interfaces of smart energy, for use inside the building microgrid. Other services will interact with the business, linking corporate calendars to building operations. Another will request and consume weather information; if nothing else, a data center should take advantage of a cold winter such as this to limit cooling loads.
Systems must tie their information to the space that the enterprise inhabits. It is not enough for points to self-describe themselves as an air handler—that air handler must describe itself in terms of the service it provides to a particular space. Space is what the building systems support, space is what the tenants recognize.
There is an enterprise service that links between the occupants and their activities and the BAS and its performance. It communicates to support business activities while using the common schedule communications developed for smart grids. It is aware of the market conditions and deals made with the grid though the ESI. It knows whether the volatile energy of the renewables-based grid is scarce or abundant. It can report back to the enterprise how and where energy is being used right now.
Even live-load, or plug-load, must be able to describe itself in relation to space. Panel sub-metering and BIM-based circuit tracing (PLie – panel layout information exchange) put even the coffee pot and copier as part of the BIM model for energy use. Even home appliances must be participants.